Herb Curl says,

> Species don't have to be any smarter
> than they need to be for survival so my question is: why have some species
> evolved smarts that they use for play, building destructive devices, or
> figuring out that there might be a hole in a fence?

I'll try one of my general answers on general principles, and then Dennis
Paulson can give you a better answer about birds in particular and
explain why I'm wrong. The general principles are about the opportunism
of evolution and about strategies. Although some people object to the
terminology, it's useful (I think) to say that every species is following
some strategy that allows it to survive (or some cluster of strategies,
if you will); and it's led into each strategy opportunistically, by
taking advantage (through selection) of whatever genetic opportunities
arise by chance. This is what Jacques Monod discussed in his book
"Chance and Necessity." Certain genetic features are produced by chance,
in an absolutely unpredictable way; but then natural selection operates
on those randomly produced DNA sequences and molds organisms with
features that have survival value. Most bird species evidently get along
very nicely with fixed-action patterns of behavior that are genetically
encoded. They have little need to learn anything and little brain power
for doing any learning. But some protocorvids, for instance, got a string
of mutations and genetic recombinations that opened up a different path,
a strategy of surviving by learning, by intelligence; their
descendants, millions of years later are following that strategy, and
entertaining us with all the neat, playful things that intelligent birds
can do. Probably no one can say why corvids and a few other families
have been shaped into using strategies of intelligence, but I think it's
fair to say that these birds now occupy different adaptive zones from
other birds--they've been taken out of competition with many other
species, and maybe that's sufficient explanation in itself. That is,
interspecific competition is supposed to be a major factor in evolution,
and any species that wanders into a way of life with reduced competition
has an advantage. Anyone have a better explanation about these birds
specifically?

Burt Guttman guttmanb at elwha.evergreen.edu
The Evergreen State College Voice: 360-866-6000, x. 6755
Olympia, WA 98505 FAX: 360-866-6794